Transmission reverse gearing



Feb. 16, 1943.

T. BACKUS TRANSMISSION REVERSE GEARING Filed Sept. 17, 1942 w 2 Sheets-Sheet 1 INVENTOR. @0/2746 flea/r03 Feb; 16, 1943- I T; BACKUS 2,311,201

- TRANSMISSION REVERSE GEARING Y Filed Sept. 17, 194k 2 Sheets-Sheet 2 1 I INVENTOR. 70mm; flack/Ls Patented Feb. 16, 1943 TRANSMISSION REVERSE GEARING Thomas Backus, Kalamazoo, Mich, assignor to Fuller Manufacturing Company, Kalamazoo,

Mich.

- Application September 17, 1942, Serial No. 458,668

2 Claims.

This invention relates to improvements in transmission reverse gearing.

This invention relates to change speed transmissions and particularly to the arrangement of the gearing for reversing. Ithas for its objects:

First, to provide a new and improved change speed transmission.

Second, to provide such a transmission with an arrangement of gearing for reversing the transmission which can be shifted into and out of operation by a very short movement of the gear shifting lever in the cab of a vehicle in which the transmission is employed.

Third, to provide such a transmission which is simple and inexpensive to manufacture.

Other objects and advantages pertaining to details and economies of construction and operation will appear from the description to follow. Preferred embodiments ofmy invention are illustrated in the accompanying drawings, in which:

Fig. 1 is a detail sectional view of a transmission embodying my invention taken on the line I--I of Fig. 2.

Fig. 2 is an end View of the various shafts and gearing employed in the transmission.

Fig. 3 is a view corresponding to Fig. 1 of a different form of the invention.

In Figs. 1 and 2, I show a five-speed constant mesh transmission embodying one form of the invention. The transmission comprises a casing I, a main shaft 2, a countershaft 3 and an input shaft 4. The input shaft 4 which is mounted in a suitable bearing 5 has an integral gear 6 which meshes with a gear I non-rotatably mounted on the countershaft. The main shaft is supported by pilot bearing 8 in the gear 6 and bearings 9 and I0. The countershaft is supported by bearings II and I2. On the main shaft are gears I3, I4 and I5 which are helical gears in constant mesh respectively with gears I6, I! and I8 which are fixed on the countershaft. The gears I3, I4 and I 5 are bushed on the main shafting. I provide a clutch member I9 splined on the main shaft and having two sets of clutch teeth 20 and 2| adapted to selectively engage clutch teeth 22 on the gear 6 or clutch teeth 23 on the gear I3.

splined to the main shaft is a shiftable member 24 which comprises an axially shiftable clutch member adapted to selectively engage either the clutch teeth 25 on gear I4 or the clutch teeth 26 on the gear I5. The member 24 likewise serves as a reverse gear since it has a plurality of peripherally arranged spur gear teeth 21 which are adapted to mesh with the spur gear teeth 28 on reverse idler gear 29.

On the countershaft, I provide also a fixed gear 30 which is in mesh with a reverse idler gear 3!. The reverse idler gears 29 and SI are both bushed on an enlarged and a reduced portion, respectively of a fixed reverse idler shaft 32, said enlarged and reduced portions providing a shoulder therebetween to confine the gear 3I against axial movement in one direction on the shaft 32. The gear 3I is rotatable and driven by the gear 30. It is a stem gear having clutch teeth 33 thereon which are adapted to mesh with clutch teeth 34 on the gear 29. The gear 29 is shiftable axially to engage clutch teeth 33 and 34 or to disengage them. When the clutch teeth 33 and 34 are in engagement, the teeth 28 of the gear 29 mesh with the teeth 2? of the member 24 which in neutral position, as illustrated in Fig. 1, serves as a reverse gear. The clutch teeth 33 and 34 are of such axial length and are so positioned that an axial movement of the teeth 28 a distance equal to the width of the teeth 21 on the member 24 to disengage the gear 29 from the member 24 which serves as a reverse gear will disengage teeth 33 and 34.

In Fig. 1, the transmission is shown with the reverse gearing disengaged. The reverse gearing is engaged when the member 24 is in the position shown in Fig. 1 and when the gear 29 is shifted to the left as viewed in Fig. 1 to pick up the teeth 21 and to engage the clutch teeth 33 and 34. The drive is then from the input shaft 4 through the gear 6 to the gear I and from the gear 30 to the gear 3|, thence through clutch teeth 33 and 34 to the gear 29 and thence to the member 24 which serves as a main shaft reverse gear. The engagement and disengagement of the clutch teeth 33 and 34 is accomplished by a movement of the gear 29 Within a distance substantially equal to the width of the teeth 21 and this makes it possible to engage or disengage the reverse gearing by a very short movement of the gear shifting lever, which is common to vehicles employing change speed transmissions. The structure is thus extremely practical and useful since cab space in a truck is at a premium.

In Fig. 3, I show a different form of the invention. There is a casing IOI, a main shaft I02, a countershaft I03 and an input shaft I04. There are suitable bearings I05, I08, I09, III, II2. There is a gear I01 fixed to the countershaft I03 and there are gears H3 and. II 4 in mesh respectively with gears H6 and H1 fixed to the countershaft. There is a clutch member II9 having clutch teeth I29 and I2I adapted to mesh selectively with clutch teeth I22 on the gear I06 and clutch teeth I23 on the gear II3.

There is a reverse gear I24 having spur teeth I21. This gear is splined on the main shaft and is provided with clutch teeth I25 adapted to mesh with clutch teeth I25 on the gear H4. The gear I24 serves both as a reverse gear and as a low gear. It is shiftable to the right from the position shown in Fig. 3 to pick up the countershaft I92 gear I I8. When it is in the neutral position, shown in Fig. 3, it serves as a main shaft reverse gear.

Mounted in the transmission is a fixed reverse idler shaft I32. It has bushed thereon a gear I 3| which is driven by a reverse countershaft gear I30. Slidably and rotatably bushed on the coun-' tershaft I32 is a second reverse idler gear I29 having spur teeth I28. The gear I3I is provided with clutch teeth I 33 and the gear I29 is provided with corresponding clutch teeth I34. The gear I29 may be slid to the left as viewed in Fig. 3 to pick up the gear I24 when it is in the position shown in Fig. 3 and to simultaneously engage clutch teeth I33 and I34. When this is done, the reverse gearing is in operative position and the drive is from shaft I 64 through gear IRS to gear I01 and from gear I30 to gear I3l thence through clutch teeth I33 and I34 to gear I29 and thence to gear I24.

The clutch teeth I33 and I34 are of such length that a shifting of the gear I29 to the right from engaged position a distance equal to the width of the gear I24 to disengage gears I29 and I24 will likewise disengage clutch teeth I33 and I34.

This arrangement using a spur gear low has the same advantages as the structure shown in Figs. 1 and 2. The shift to engage or disengage the low gear is a short one and this permits a short shift lever movement to accomplish the results.

This construction of the reverse gearing can be made very inexpensively. The mounting of the fixed reverse idler shaft is simple and the bushing of the gears thereon is not involved. The gears and clutch teeth can be made very easily and inexpensively on ordinary gear cutting equip ment.

The terms and expressions which have been herein employed are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described, or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.

Having thus described my invention, what I claims as new and desire to secure by Letters Patent is:

1. In a change speed transmission having a main shaft and a countershaft with cooperating gears thereon and a non-rotatable reverse idler shaft having enlarged and reduced portions, a first rotatable reverse idler gear on a reduced portion of said idler shaft, a gear on said countershaft in mesh with said first reverse idler gear to drive the same, a second reverse idler gear on an enlarged portion of said idler shaft and shiftable axially and rotatable relative to said first reverse idler gear, said enlarged and reduced portions providing a shoulder to confine said first idler gear against axial movement on said idler shaft, cooperating clutch teeth on said first and second reverse idler gears, and a main shaft gear on said main shaft and adapted to mesh with said second reverse idler gear when said clutch teeth are engaged, said clutch teeth being disengageable by shifting said second reverse idler within a distanct equal substantially to the width of said main shaft gear,

2. In a change speed transmission having a main shaft and a countershaft with cooperating gears thereon, a fixed reverse idler shaft, a first reverse idler gear bushed for rotation on said idler shaft, a gear on said countershaft in mesh with said first reverse idler gear to drive the same, a second reverse idler gear bushed for rotation on said idler shaft and shiftable axially thereon, said second idler gear being rotatably supported on said fixed idler shaft independently of said first idler gear, cooperating clutch teeth on said first and second reverse idler gears, and

a main shaft gear on said main shaft and adapted to mesh with said second reverse idler gear when said clutch teeth are engaged, said clutch teeth being disengageable by shifting said second reverse idler within a distance equal substantially to the width of said main shaft gear.

THOMAS BACKUS. 

